HER2 is part of a highly complex signalling pathway that plays a key role in the growth, repair and survival of cardiac myocytes.^1-6 As Herceptin^® successfully inhibits HER2 signalling, it can also modify cardiac function especially when given in combination with, or proximity to, cardiotoxic chemotherapies such as anthracyclines. Careful consideration of pre-Herceptin^® cardiac status and appropriate cardiac monitoring during treatment is, therefore, essential.

Figure 1.3 Cardiac criteria for initiating Herceptin® therapy2 (reproduced by kind permission of the author)

Clinical trials in both MBC and EBC have shown that by using stringent cardiac screening and monitoring procedures, cardiac dysfunction during Herceptin^® treatment is infrequent.^3-8

Table 1.2 Low rate of cardiac dysfunction during Herceptin® trials in MBC and EBC3-8

Evidence suggests that most Herceptin^® -related cardiac dysfunction occurs during treatment and very few occur after cessation of Herceptin^® therapy.^5,6 When Herceptin-related cardiac events do occur, they are manageable and largely reversible and do not exclude patients from further treatment with Herceptin.